Colin Firth and Michael Palin on red carpet for The King's Speech

Monty Python star Michael Palin joined actor Colin Firth at a charity screening of The King's Speech, a film he hopes will prove "stammerers are no different from anybody else."

Palin's father had a severe stammer and he himself famously played a man with a stammer in comedy film A Fish Called Wanda.

The King's Speech, which has already been tipped as an Oscar winner, is based on the true story of how King George VI, played by Firth, as he attempts to overcome his stammer with the help of irreverent Australian speech therapist Lionel Logue.

Palin said on the red carpet: "I think [the film] could make an enormous difference because it's very important to see people with stammers as just the same as anyone else. They laugh the same, they cry the same, one just has the slight problem of speaking fluently.

"It's very important to show that a stammer isn't just a comedy vocal touch [and that] stammerers are no different from anybody else."

The screening, which was also attended by director Tom Hooper, raised money for The Michael Palin Centre For Stammering Children, a specialist centre the actor gave his name to after playing Ken in the 1988 film.

"It caused a bit of debate: should you portray a stammerer on film? But it was a successful film and it got me thinking, particularly about my father's stammer," he said.

Palin added he often thought of how different his father's life would have been if he had had access to a similar centre.

He said: "My father never recovered from it. It was quite severe, and we just took it for granted, that was the way he was and we couldn't do anything about it.

"It really must have made his life a misery."

Firth revealed that even to this day his speech had been affected by playing a stammering character.

"If I start thinking about it there's the danger it will kick in again," he said.

Helena Bonham Carter plays Queen Elizabeth in the film, although she was unable to attend the screening after being caught in traffic, organisers said.The King's Speech is out in cinemas on January 7.